1 //===-- X86InstrBuilder.h - Functions to aid building x86 insts -*- C++ -*-===//
3 // This file exposes functions that may be used with BuildMI from the
4 // MachineInstrBuilder.h file to handle X86'isms in a clean way.
6 // The BuildMem function may be used with the BuildMI function to add entire
7 // memory references in a single, typed, function call. X86 memory references
8 // can be very complex expressions (described in the README), so wrapping them
9 // up behind an easier to use interface makes sense. Descriptions of the
10 // functions are included below.
12 // For reference, the order of operands for memory references is:
13 // (Operand), Base, Scale, Index, Displacement.
15 //===----------------------------------------------------------------------===//
17 #ifndef X86INSTRBUILDER_H
18 #define X86INSTRBUILDER_H
20 #include "llvm/CodeGen/MachineInstrBuilder.h"
22 /// addDirectMem - This function is used to add a direct memory reference to the
23 /// current instruction -- that is, a dereference of an address in a register,
24 /// with no scale, index or displacement. An example is: DWORD PTR [EAX].
26 inline const MachineInstrBuilder &addDirectMem(const MachineInstrBuilder &MIB,
28 // Because memory references are always represented with four
29 // values, this adds: Reg, [1, NoReg, 0] to the instruction.
30 return MIB.addReg(Reg).addZImm(1).addReg(0).addSImm(0);
34 /// addRegOffset - This function is used to add a memory reference of the form
35 /// [Reg + Offset], i.e., one with no scale or index, but with a
36 /// displacement. An example is: DWORD PTR [EAX + 4].
38 inline const MachineInstrBuilder &addRegOffset(const MachineInstrBuilder &MIB,
39 unsigned Reg, int Offset) {
40 return MIB.addReg(Reg).addZImm(1).addReg(0).addSImm(Offset);
43 /// addFrameReference - This function is used to add a reference to the base of
44 /// an abstract object on the stack frame of the current function. This
45 /// reference has base register as the FrameIndex offset until it is resolved.
46 /// This allows a constant offset to be specified as well...
48 inline const MachineInstrBuilder &
49 addFrameReference(const MachineInstrBuilder &MIB, int FI, int Offset = 0) {
50 return MIB.addFrameIndex(FI).addZImm(1).addReg(0).addSImm(Offset);
53 /// addConstantPoolReference - This function is used to add a reference to the
54 /// base of a constant value spilled to the per-function constant pool. The
55 /// reference has base register ConstantPoolIndex offset which is retained until
56 /// either machine code emission or assembly output. This allows an optional
57 /// offset to be added as well.
59 inline const MachineInstrBuilder &
60 addConstantPoolReference(const MachineInstrBuilder &MIB, unsigned CPI,
62 return MIB.addConstantPoolIndex(CPI).addZImm(1).addReg(0).addSImm(Offset);